When I first started using WPMU, the now-integrated multisite version of WordPress, I found it strange that there were no built-in tools to aggregate content onto the main blog. It seemed to me that that was something plenty of people would want to do. Sure, there were plugins and hacks, but none of them were as polished as I’d like them to be.
Fortunately, things have changed. WordPress 3.0 now has multisite capabilities built right into it, and Bjorn Wijers, a friend of mine and one of Holland’s top WordPress developers, has created a really cool plugin to handle content aggregation. Called bbAggregate, this plugin doesn’t just collect posts from blogs to be displayed on the home page, it allows you to display aggregated content on any of your network’s blogs. And to do this it introduces the concept of streams.
More bbAggregate lets you mix and match WordPress content